Nodal Staging in Patients with Locally Advanced Non-Small Cell Lung Cancer: Indications, Approaches, and Impact on Downstream Treatment Selection

Locally advanced non-small cell lung cancer (NSCLC) is a biologically and clinically heterogeneous disease in which mediastinal lymph node involvement remains the principal prognostic and therapeutic discriminator. Accurate nodal staging guides selection among surgical resection, definitive chemoradiotherapy, immunotherapy, and targeted therapy. This narrative review synthesizes contemporary evidence on mediastinal staging modalities, nodal disease burden, and treatment selection in stage II-III NSCLC. Contemporary staging integrates CT and FDG-PET/CT with systematic tissue confirmation using EBUS-TBNA and EUS, with surgical mediastinal staging reserved for selected high-risk or discordant cases. The ninth edition TNM N2a/N2b distinction, increasing use of neoadjuvant and perioperative immunotherapy, and molecularly guided therapy have further amplified the clinical consequences of under- or over-staging. Nodal assessment should therefore be interpreted through a multidisciplinary framework that integrates anatomy, biology, treatment response, and patient operability.